当前位置：网站首页>Calculate the number of combinations recursively

Calculate the number of combinations recursively

2022-08-10 13:20:00 【51CTO】

Approximate title:

Calculate the number of combinations according to the formula given in the title.

Thinking:

Use a recursive function to recursively solve the number of combinations.

Thinking:

Generally, most of the questions with formulas use recursion.

Code:

#include 

using namespace std ;
int f ( int a , int b )
{ if (b == 0 ) return 1 ;
else { if (a == 1 ) return 1 ;
else { if (a ==b ) return 1 ;
else { return ( f (a -1 ,b -1 )+ f (a -1 ,b )); }}}

}


int main()

{ int n ;
cin >>n ;
int a ,b ;
while (cin >>a )
{
cin >>b ;
cout << f (a ,b )<n --;
if (n <= 0 ) break ;
}
 return 0 ;
}
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.